Process of making nitrogen compounds.



latented March 21, 1905 ATENT @FNCE,

NBUKG, AND NIKMHCU (mike, or mantis,

(ilili MAN Y.

PROCESS OF MAKING NITROGEN COMPOUNDS.

SPECIFICATION forming part of Letters Patent No. 785,161,

dated March 21, 1905.

Application filed December Z0, 1898. Serial N 699,847-

T 0 (LZZ whorl 1, it may concern;

Be it known that we, ADoLPH FRANK, of (lharlotten burg, and N IKODEM CARo, of Berlin, Germay, have invented certain new and usei113 Improvements in the Manufacture of Nitrogen Compounds; and we do hereby declare the following to be a full, clear, and exact deseription of the invention, such as will enable others skilled in the art to which it HDDQliZfiiIlS to make and use the same,

As is well known and as confirmed by Moisson, (Com ot/1s Remix s for 1894, page 503,) no reaction or combinatirm takes place when nitrogen is brought into contact with a heated 5 carbid. We have, however, discovered that suitably-heated carbids will absorb nitrogen under certain conditions for instance, in the presence of aqueous vapor, as described in our British Patent No. 15,066, of August 10,

I895, and in our patent of the United States, No. 590,217, of September 21, 1897, or in they presence of an oxid of a metal, as described in our patentofthe United States, No. 623,709, of April 25, 1899- and that cyanids corre- 5 spending to the tear-bid used are obtained from the products of the reaction.

Although the yield of cyanid by the processes described is highly satisfactory, yet it appeared to us to be inadequate, and this led 3 us to further investigation, which resulted in the discovery of the cause of it, which we foundto be due to a great portion of the nitrogen being fixed in theform of other nitrogen compounds nmnely, in the form of cyanan'iids, also called amidocyanhl and amidooxycyaniil bid according to the following equation:

4 which were practically lost in the former proccsscs.

We have, furtl'iermorc, discovered that the satisfactory yield in cyanhl by the processes described in our patents above referred to was due chiefly to the more or less complete melting of the carbid or. the carbid-forming mixture during the reaction and that this also has a disadvantage in that it A prevents thabsorgition of nitrogen to a great extent, while subin the case of calcium cari l i I l l i i stantially complete absorption or saturation 5 takesplace when the carbid remains unmeltedthat is to say, in a p'ulverulent or porous state.

As is well known, the earbids of the alkalies, such as sodium and potassium earbid, melt at the temperatures to which they must be heated namely, to from a dark-red to'a bright-yellow hcat----in order to readily ab sorb nitrogen, while the meltingpoint of other carbi(ls- -as, for instance, barium carbid --is so close'to that temperature that melting can hardly be prevented, especially when compounds of the carbid containiugsubstances which melt at those temperatures or at a lower temperature are employed, such sub-. 6 5 stances acting as a flux. This, however, is not the ease with calcium and some other carbidsthe meltingpoint of which is much higher than. thetemperatures to which they are to be heated for the ready absorption of 7. nitrogen. These investigations and experiments led us to the discovery of dividing the process into two separate steps, consisting in first reacting with nitrogen upon certain carbids or carbid-forming mixtures heated to a temperature below their melting-point, but sufficiently high to readily absorb nitrogen, whereby the cyanamids above referred to are chiefly formed, and then melting the reaction product to convert the cyanamids into cyanid. 0

In carrying out our invention pure nitrogen or nitrogen cmnpoumls, as ammonia, may be use'ill, and we proceed as follows: The calcium carbid, for instance, is heated in a suitable furnace to a tcn'iperaturc below the melt- 5 ing-poi'nt, preferably not higher than toadarkred or bright-yellow heat, or to a temperature which may vary from aboutUU O to 1,000 centigrade, and'is then reacted on with nitrogen until absorption of the latter ceases. As the 96 carbid is not melted, there is no interference with the absorption of nitrogen, which thus proceeds much more rapidiy and completely, whilecyanamid is chiefly formed, which inthe older processes was lost to a great extent and whiclrniay be extracted as hereinafter described. 'T- onvertthiscyauamidintocyanid, the product -f' the reaction is removed from the furnace and melted, which is materially facili- .tatcd and expedited by .the addition thereto before or during melting of a suitable flux for instance, caustic soda, caustic potash, sodium carbonate, potassium carbonate, or other suitable salts. As a certain proportion of carbon is set free during the action of the nitrogen on the carbid' and should the prodact of the reaction be deficient in carbon, it is advantageous to make up the deficiency by the addition ofa quantity of carbon. On the other hand, the product of the reaction should contain suiiicient of the baseto bind the cyanogen formed by the melting of the said product, and if this should not be the case a basic substance-for instance, an oxygen compound ofthe alkalies or of the alkaline earths, such as caustic soda, caustic potash, sodium, or potassium carbonate, lime, calcium carbonate. or the like is also added, which may ofcourse also be used as fluxes, as above stated.

By the melting of the reaction product the 'metal compoundfor instance, of the calcium cyanid formed-namely, the cyanamid UaNCN--is converted into cyanid according to the equation (laNUN+C:Ca(C-Nh and is extracted in the usual manner. Cyanamid may, however, be obtained by'leaching it out of the reaction product with water and extracting it from the solution by rneans of a.

suitable solvent, as ether, from which it may be obtained by evaporation.

Any carbid that will not melt when heated to front a dark-red to a bright-yellow heat can therefore be employed in our process, and it isvof course immaterial in what form the earbid is used, whether as suchri. c., pure carbid or carbid in the process of formationor in the form of its reaction components. The term carbid is therefore intended to cover any form of such.

red to a bright-yellow heat, a carbid that will I not melt at these temperatures, reacting upon the heated earbid with i'iitrogmi, then melting the product of the reaction and extracting the cyanid in the usual manner, substan-' tially as set forth.

2.* The process, which consists in heating to from a dark-red to, a bright-yellow heat carbid that will not melt at these temperatures,

reacting upon the heated carbid with nitro gen, then melting the reaction product in the presence of carbon and extracting the cyanid in the usual manner, substantially as set forth.

3. The process, which consists in heating to from a dark-red to a bright-yellow heata car-. bid that will not melt at these temperatures, reacting upon the heated cal-bid with nitrogen, melting the reaction product in the presence of an oxygen compound of an alkaline metal and extracting the cyanid in the usual manner, substantially as set forth.

at. The process, which consists in heating'to from a dark-red to a bright-yellow heat a carbid that will not melt at these temperatures, reacting upon the heated carbid with nitrogen, leaching the cyanarnid out of the reaction product, then melting the latter and extracting' the cyanid in the usual manner.

in testimony whereof We affix our signatures in presence of two witnesses.

ADOLPH FRANK.

NIKODEM CARO.

Witnesses:

ERWIN L. GoLnsontiuIDT, MAX. C. STAEHLER. 

